1. Field of the Invention
The invention relates to a window mechanism for a sensor in an industrial robot.
2. Description of the Related Art
Various automatic machining processes are realized by an industrial robot with an end effector such as a welding device or a laser beam machining device mounted onto the distal end of a robot arm. In order to optimize the machining process, a sensor is provided for detecting a locational or dimensional error of the workpiece. The process is carried out after correcting the error. In general, the sensor is disposed inside or outside the end effector at the distal end of the robot arm.
When the end effector is a welding device or laser beam machining device, a sensor of the non-contact type, such as an infrared sensor or a laser sensor, is suitable. The welding process and the laser beam machining process generate high temperature gas, fumes and spatters. In order to protect the sensor from the high temperature gas, fumes and spatters, the sensor is enclosed in the housing of the end effector or in a separate housing for the sensor. The housing, in which the sensor is provided, has a window through which the infrared beam or the laser beam is projected and the reflection thereof is received. The window includes a slot or an opening which is covered by a closing member such as a glass plate.
The outer surface of the closing member becomes contaminated by the spatters and fumes from the machining region. When the contamination on the outer surface of the closing member is extensive, the sensor cannot function. In order to prevent this, it is necessary to remove the spatters or fumes on the outer surface of the closing member or to exchange the closing member at intervals. In the prior art, these operations were carried out by an operator, which results in increasing the time and cost for the machining process.